Finding the Third Proportional to 111.25 and 128

Step by Step Solution

1. Step 1: Write the proportion equation
   111.25 : 128 = 128 : x
2. Step 2: Convert to fraction form
   111.25/128 = 128/x
3. Step 3: Cross multiply
   111.25x = 128 × 128
4. Step 4: Simplify right side
   111.25x = 16,384
5. Step 5: Solve for x
   x = 16,384/111.25
6. Step 6: Final answer
   x = 147.27